Bump DeterminateSystems/nix-installer-action from 8 to 9 (#60)

Bumps [DeterminateSystems/nix-installer-action](https://github.com/determinatesystems/nix-installer-action) from 8 to 9.
- [Release notes](https://github.com/determinatesystems/nix-installer-action/releases)
- [Commits](DeterminateSystems/nix-installer-action@v8...v9)

---
updated-dependencies:
- dependency-name: DeterminateSystems/nix-installer-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/build-slides.yml

@@ -20,7 +20,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v8
+        uses: DeterminateSystems/nix-installer-action@v9
 
       - name: Cache Nix artifacts
         uses: DeterminateSystems/magic-nix-cache-action@v2

.github/workflows/models.yml

@@ -39,7 +39,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v8
+        uses: DeterminateSystems/nix-installer-action@v9
 
       - name: Cache Nix artifacts
         uses: DeterminateSystems/magic-nix-cache-action@v2
@@ -146,7 +146,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v8
+        uses: DeterminateSystems/nix-installer-action@v9
 
       - name: Cache Nix artifacts
         uses: DeterminateSystems/magic-nix-cache-action@v2

.github/workflows/release-slides.yml

@@ -16,7 +16,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v8
+        uses: DeterminateSystems/nix-installer-action@v9
 
       - name: Cache Nix artifacts
         uses: DeterminateSystems/magic-nix-cache-action@v2

.github/workflows/update_flake_lock.yml

@@ -11,7 +11,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v8
+        uses: DeterminateSystems/nix-installer-action@v9
       - name: Update flake.lock
         uses: DeterminateSystems/update-flake-lock@v20
         with: